1. Field of the Invention
The present invention relates to an input device, and more particularly, to an input device on which a coordinate input operation and a pressing operation can be performed.
2. Description of the Related Art
An input device that detects a contact operation position in various manners, such as a pressure-sensitive type of sensing contact pressure and reacting or a capacitive type of reacting to a change in capacitance between a finger and a conductive film has been conventionally known.
Since an operator can perform an intuitive input operation, such an input device is widely used for a portable device such as a laptop personal computer, a portable phone, or a tablet terminal or an in-vehicle device such as a navigation device.
Further, an input device on which a pressing operation can be performed together with a contact operation so as to realize a variety of input operations with high performance or the like of the above-described device has been proposed.
An input device 900 described in Japanese Unexamined Patent Application Publication No. 2007-304757 (related art) includes an input pad 924 that can detect a contact position of an operation body, and a data processing unit that analyzes the contact position of the operation body in the input pad 924, is provided in which a switch 922 of which the output is switched when the input pad 924 is pressed, as illustrated in FIG. 9.
In the data processing unit, when the input pad 924 detects the contact of the operation body without the output of the switch 922 being switched, a range including a plurality of areas is a coordinate input portion, and coordinate data corresponding to a position with which the operation body comes in contact in the coordinate input portion is generated as a pad input signal. Further, when the output of the switch 922 is switched, the data processing unit detects which of a plurality of areas divided on the input pad 924 corresponds to the contact position of the operation body, and generates a different input signal for each area with which the operation body comes in contact.
As described above, the input device on which a variety of operation inputs can be performed using the input pad through a combination of the input pad and the switch has been disclosed.
However, in the input device of the related art described above, changing the contact area of the finger of the operator with an operation surface as pressure from the finger applied to the operation surface at the time of a pressing operation increases has not been considered. FIGS. 10A and 10B are schematic views illustrating a relationship between a contact area R of a finger as an operation body F and a center coordinate C, FIG. 10A is a view illustrating a case in which a contact operation is performed with the finger without performing a pressing operation, and FIG. 10B is a view illustrating a case in which the pressing operation is performed with the finger. The contact area R of the finger as the operation body F is relatively small in a state in which the finger is not used to press as illustrated in FIG. 10A, but the contact area R increases due to operation pressure as illustrated in FIG. 10B when the pressing operation is performed with the finger. A position of the center coordinate C of a contact range is shifted due to a change in the contact area R of the operation body F. Further, the positional shift occurring in this way is smaller when the finger is perpendicularly close to the operation surface, and is greater in a state in which the finger lies along the operation surface. Therefore, there is a problem in that the center coordinate C may be changed due to the pressing operation since the contact area R of the finger of the operator is changed at the time of the pressing operation, and the contact area R of the finger is changed greatly and easily in a place away from an end on the side of the input device that the finger approaches.